Reading device, image processing device, reading method, and program

Abstract

To enable an automatic size detection result to be acquired with sizes being close to the actual sizes of subjects when subjects having different sizes of fixed sizes and non-fixed sizes are mixed while preventing information loss.SOLUTION: A device includes an illumination unit that irradiates a subject with light, an imaging unit that receives light reflected by the subject to generate an image, a first width detection unit that detects the width of the subject, a second width detection unit that detects the width of the subject using a method different from that of the first width detection unit, and a width determination unit that determines the size of the subject. The width determination unit determines the width of the subject based on the detection result of the first width detection unit when the detection by the first width detection unit is normal, and determines the width of the subject based on the detection result of the second width detection unit when the detection by the first width detection unit is abnormal.SELECTED DRAWING: Figure 15

Description

Technical Field

[0001] The present invention relates to a reading device, an image processing device, a reading method, and a program.

Background Art

[0002] Conventionally, in a reading device, there is known a technique of automatically detecting the size of a read subject (e.g., a document) by image processing and cutting out an image according to the detected size.

[0003] Patent Document 1 discloses a technique of determining an image size using the width of a side fence of a reading device when size detection by image processing (edge detection) fails for the purpose of automatically detecting a document size.

Summary of the Invention

Problems to be Solved by the Invention

[0004] However, in a conventional reading device, for example, when automatic size detection fails in the case of mixed loading of different widths in which a document of a fixed size and a document of an irregular size are mixed, a size that is significantly different from the correct document size is detected by using the width of the side fence instead of the width of the subject, and there is a problem that information may be lost due to a part of the cut-out image being missing according to the detected size.

[0005] The present invention has been made in view of the above, and an object thereof is to be able to detect an automatic size detection result at the time of mixed loading of different widths including a subject of a fixed size and a subject of an irregular size with a size close to the actual size of the subject and to prevent information loss.

Means for Solving the Problems

[0006] In order to solve the above-described problems and achieve the object, the present invention includes an illumination unit that irradiates light onto a subject, an imaging unit that receives the light reflected by the subject and generates an image, a first width detection unit that detects the width of the subject, a second width detection unit that detects the width of the subject by a method different from that of the first width detection unit, and a width determination unit that determines the size of the subject. When the detection by the first width detection unit is normal, the width determination unit determines the width of the subject based on the detection result of the first width detection unit. When the detection by the first width detection unit is abnormal, the width determination unit determines the width of the subject based on the detection result of the second width detection unit.

Effect of the Invention

[0007] According to the present invention, it is possible to detect the automatic size detection result when different-width objects including fixed-size and non-fixed-size objects are mixed at a size close to the actual size of the object, and to prevent information loss.

Brief Description of the Drawings

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Embodiments for Carrying Out the Invention

[0009] Hereinafter, embodiments of a reading device, an image processing device, a reading method, and a program will be described in detail with reference to the accompanying drawings.

[0010] (First Embodiment) FIG. 1 is a diagram showing a configuration example of an image forming apparatus 1 according to the first embodiment. In FIG. 1, the image forming apparatus 1 which is an image processing apparatus is generally called a multi-function device having at least two functions among a copying function, a printer function, a scanner function, and a facsimile function.

[0011] The image forming apparatus 1 has an image reading apparatus 101 which is a reading device, and has an image forming unit 103 below it. Regarding the image forming unit 103, in order to explain the internal configuration, the external cover is removed to show the internal configuration.

[0012] The image reading apparatus 101 mounts an ADF (Automatic Document Feeder) 102 on the upper part of the apparatus main body 10. The ADF 102 is a document support unit that positions a document for reading at the reading position. The ADF 102 automatically conveys the document placed on the placement table to the reading position. The image reading apparatus 101 reads the document conveyed by the ADF 102 at a predetermined reading position. Further, the image reading apparatus 101 has a contact glass which is a document support unit for placing a document on the upper surface, and reads the document on the contact glass which is the reading position. Specifically, the image reading apparatus 101 is a scanner having a light source, an optical system, and a solid-state imaging device such as a CMOS image sensor inside, and reads the reflected light of the document illuminated by the light source with the solid-state imaging device through the optical system.

[0013] The image forming unit 103 includes a manual roller 104 that accepts manual feeding of recording paper, and a recording paper supply unit 107 that supplies the recording paper. The recording paper supply unit 107 has a mechanism for feeding out the recording paper from a multi-stage recording paper cassette 107a. The supplied recording paper is sent to the secondary transfer belt 112 via a registration roller 108.

[0014] The recording paper conveyed on the secondary transfer belt 112 has the toner image on the intermediate transfer belt 113 transferred thereto in the transfer unit 114.

[0015] Also, the image forming unit 103 includes an optical writing device 109, a tandem type image forming unit (Y, M, C, K) 105, an intermediate transfer belt 113, the secondary transfer belt 112, and the like. The image forming unit 103 forms the image written by the optical writing device 109 as a toner image on the intermediate transfer belt 113 by an image forming process performed by the image forming unit 105.

[0016] Specifically, the image forming unit (Y, M, C, K) 105 rotatably has four photosensitive drums (Y, M, C, K), and each photosensitive drum is provided with an image forming element 106 including a charging roller, a developing device, a primary transfer roller, a cleaner unit, and a discharger around its circumference. The image forming element 106 functions on each photosensitive drum, and the image on the photosensitive drum is transferred onto the intermediate transfer belt 113 by each primary transfer roller.

[0017] The intermediate transfer belt 113 is stretched and arranged by a driving roller and a driven roller at the nip between each photosensitive drum and each primary transfer roller. The toner image primarily transferred onto the intermediate transfer belt 113 is secondarily transferred onto the recording paper on the secondary transfer belt 112 by a secondary transfer device due to the running of the intermediate transfer belt 113. The recording paper is conveyed to a fixing device 110 due to the running of the secondary transfer belt 112, and the toner image is fixed as a color image on the recording paper. Thereafter, the recording paper is discharged to an external paper discharge tray. In the case of double-sided printing, the front and back of the recording paper are reversed by a reversing mechanism 111, and the reversed recording paper is sent onto the secondary transfer belt 112.

[0018] Note that the image forming unit 103 is not limited to forming an image by the electrophotographic method as described above, and may form an image by an inkjet method.

[0019] Next, the image reading device 101 will be described.

[0020] FIG. 2 is a diagram showing an example of the device configuration of the image reading device 101. The device main body 10 of the image reading device 101 has a contact glass 11 on its upper surface. The image reading device 101 has a light source 13, a first carriage 14, a second carriage 15, a lens unit 16, a sensor board 17, etc. inside the device main body 10. In FIG. 2, the first carriage 14 has a light source 13 and a reflection mirror 14-1, and the second carriage 15 has reflection mirrors 15-1 and 15-2.

[0021] The light of the light source 13 is irradiated onto the object to be read, and the reflected light from the object to be read is reflected by the mirror 14-1 of the first carriage 14 and the mirrors 15-1 and 15-2 of the second carriage 15 and enters the lens unit 16, and an image of the object to be read is formed on the light receiving surface on the sensor board 17 from the lens unit 16. The sensor board 17 has an imaging unit 40 which is a line sensor such as a CCD (Charge Coupled Device) or a CMOS (Complementary MOS). The sensor board 17 sequentially converts the image of the object to be read formed on the light receiving surface in the imaging unit 40 into an electrical signal. The reference white board 12 is a white density reference member that is read for correction of changes in the light amount of the light source 13 and variations in pixels (pixel circuits) of the imaging unit 40.

[0022] The image reading device 101 is provided with a control board in the device main body 10, and controls each part of the device main body 10 and each part of the ADF 102 to read the object to be read by a predetermined reading method. The object to be read is, for example, a recording medium on which characters, patterns, etc. are formed. Hereinafter, this recording medium will be referred to as a document. The document corresponds to the "subject", and will be described as paper or a transparent sheet (such as an OHP sheet) as an example, but is not limited thereto.

[0023] The image reading device 101 reads the document 100 in a sheet-through manner using the ADF 102. The ADF 102 is an example of a "transport unit". In the configuration shown in FIG. 2, the image reading device 101 separates the documents 100 one by one from the stack of documents on the tray 21 of the ADF 102 by the pickup roller 22, transports the document 100 to the transport path 23, reads the surface of the document 100 to be read at the reading position of the reading unit, and discharges the document 100 to the discharge tray 25. The transport of the document 100 is performed by the rotation of various transport rollers 24.

[0024] Among the various transport rollers 24, a pair of rollers that perform primary abutment alignment (so-called skew correction) on the fed document 100 and pull out and transport the aligned document 100 are called pull-out rollers 24a. A butting sensor 51 is provided near the pull-out rollers 24a.

[0025] The tray 21 has a movable document table 211 that rotates in the a and b directions in the figure with the base end as a fulcrum, and a pair of side guide plates 212 that position the document 100 in the left-right direction with respect to the paper feed direction of the document 100. By rotating the movable document table 211, the front end of the document 100 in the paper feed direction is adjusted to an appropriate height.

[0026] In addition, document length detection sensors 213 and 214 for detecting whether the document 100 is in the vertical or horizontal orientation are provided at intervals in the paper feed direction on the tray 21. Note that as the document length detection sensors 213 and 214, a reflection type sensor that detects without contact by optical means or a contact type actuator type sensor may be used.

[0027] The pair of side guide plates 212 are slidable in the left-right direction with respect to the paper feed direction, and are configured to be able to support documents 100 of different sizes. A document set sensor 215 for detecting that the document 100 is placed on the tray 21 is provided on the pair of side guide plates 212.

[0028] Further, a document width sensor 52 as a second width detection unit is provided in the conveyance path 23 on the downstream side in the document conveyance direction of the pull-out roller 24a.

[0029] Here, FIG. 3 is a diagram showing an arrangement example of the document width sensor 52. As shown in FIG. 3, the document width sensor 52 includes, as an example, light receiving elements (52a, 52b, 52c) as sensors arranged in the width direction of the document 100 in accordance with the size of the standard document of each document 100 from the side guide plate 212 serving as a document placement reference. The document width sensor 52 detects the document width of the document 100 for each document 100 (for each subject) based on the light reception result from the irradiation light provided at opposing positions across the conveyance path 23. Note that the length of the document 100 in the conveyance direction is detected from the motor pulses when the leading end and the trailing end of the document 100 are read by the abutment sensor 51 provided near the pull-out roller 24a.

[0030] The image reading device 101 passes the document 100 between the reading window 19 and the background portion 26 with, for example, the first carriage 14 and the second carriage 15 moved to a predetermined home position and fixed. The reading window 19 is a slit-shaped reading window provided in a part of the contact glass 11. The background portion 26 is a member located at a position facing the reading window 19. The reading unit irradiates the first surface (front surface or back surface) of the document 100 facing the reading window 19 side with the light of the light source 13 while the document 100 passes through the reading window 19, and receives the reflected light with the imaging unit 40 on the sensor board 17 to read an image. The background portion 26 may have a size such that it is included in the imaging range of the imaging unit 40, and is, for example, a sheet metal or a roller.

[0031] Here, the light source 13, the background portion 26, the optical system (mirrors 14-1, 15-1, 15-2, lens unit 16, etc.) that guides the reflected light from the document 100 to the imaging unit 40 of the sensor board 17, and the imaging unit 40, etc. will be described as a reading unit (first reading unit). The configuration of the reading unit will be described again with reference to FIG. 5.

[0032] When performing double-sided reading of the document 100, for example, it is carried out by providing a reversing mechanism for reversing the front and back sides. The image reading device 101 reverses the document 100 by providing a reversing mechanism and causes the second side of the document 100 to be read at the reading position (reading window 19) of the reading unit. Also, not limited to the reversing mechanism, other configurations, for example, providing a second reading unit, may be used to cause the second side to be read. For example, after passing through the reading window 19, the second side of the document 100 is read by a reading unit (second reading unit) provided on the back side of the document 100 with a reading sensor. In this case, the member at the position facing the reading sensor corresponds to the background portion 26 (see FIG. 4).

[0033] In the configuration of the image reading device 101 of this example, flatbed reading is also possible. Specifically, the ADF 102 is lifted to expose the contact glass 11, and the document 100 is directly placed on the contact glass 11. Then, the ADF 102 is lowered to its original position and the back side of the document 100 is pressed at the lower part of the ADF 102. In the flatbed method, since the document 100 is fixed, the carriage (first carriage 14, second carriage 15) side is moved relative to the document 100 for scanning. The first carriage 14 and the second carriage 15 are driven by a scanner motor 18 and scan in the sub-scanning direction of the document 100. For example, the first carriage 14 moves at a speed V, and at the same time, the second carriage 15 moves in conjunction with it at a speed of 1 / 2V, which is half the speed of the first carriage 14, to read the first side of the document 100 on the contact glass 11 side. In this case, the lower part of the ADF 102 (the member that presses the document 100 from the back) corresponds to the background portion 26 (see FIG. 4).

[0034] Note that in this example, the first carriage 14, the second carriage 15, the lens unit 16, the sensor board 17, etc. are shown separately, but these may be provided individually or as an integrated sensor module integrated together.

[0035] FIG. 4 is a diagram for explaining an example of the configuration of the reading unit 30. As an example, it shows the configuration of the reading unit 30 (first reading unit) that reads the first page of the document 100 and the transport mechanism. As shown in FIG. 4, the document 100 is sent by various transport rollers 24 and passes between the reading position (reading window 19) of the contact glass 11 and the background portion 26.

[0036] The reading unit 30 has a background portion 26 set therein. When the light source 13 is lit, while the document 100 passes through the reading window 19, the reflected light of the light from the light source 13 from the first page of the document 100 directed toward the reading window 19 is received by the imaging unit 40 on the sensor board 17 through the path indicated by the dotted line in FIG. 4, and an image is read.

[0037] Note that the configuration of the reading unit is not limited to the configuration of this first reading unit. It may be appropriately modified according to the method of reading with a close-contact type image sensor like the second reading unit or other configurations of the image reading device.

[0038] As shown in FIG. 4, the light source 13 of the present embodiment is composed of a visible light source 13a and an invisible light source 13b, and is an illumination unit that irradiates a subject with visible light and invisible light. The visible light source 13a irradiates the subject and the background portion 26 with visible light. The invisible light source 13b irradiates the subject and the background portion 26 with invisible light. It is effective to use infrared light as the invisible light source 13b. Generally, the visible light wavelength range is 380 to 750 nm, and 750 nm and above is the infrared wavelength range, which is the wavelength range of invisible light.

[0039] Note that in the present embodiment, the invisible light source 13b is assumed to irradiate invisible light in the infrared wavelength range of 750 nm or more, but it is not limited thereto, and it may irradiate invisible light in the ultraviolet wavelength range of 380 nm or less.

[0040] FIG. 5 is a block diagram showing the electrical connections of the respective parts constituting the image reading apparatus 101. As shown in FIG. 5, the image reading apparatus 101 includes, in addition to the imaging unit 40 and the light source 13 described above, a control unit 41, a light source driving unit 42, and an image processing unit 43. The control unit 41 controls the imaging unit 40, the light source driving unit 42, and the image processing unit 43. The light source driving unit 42 drives the light source 13 in accordance with the control of the control unit 41. The imaging unit 40 transfers signals to the image processing unit 43 arranged at the subsequent stage.

[0041] The imaging unit 40 includes an infrared light image sensor 40b that functions as an invisible image reading unit and a visible light image sensor 40a that functions as a visible image reading unit. The imaging unit 40 receives visible light and infrared light reflected by a subject and captures a visible image and an infrared image. More specifically, the infrared light image sensor 40b reads infrared reflected light from a subject, which is a part of infrared light, to obtain an infrared image (an image in the infrared wavelength region). The visible light image sensor 40a reads visible reflected light from a subject, which is a part of visible light, to obtain a visible image (an image in the visible wavelength region). The infrared light image sensor 40b and the visible light image sensor 40a are sensors for a reduction optical system, and are, for example, CMOS image sensors.

[0042] Note that the visible light image sensor 40a and the infrared light image sensor 40b may have an integrated configuration. As a result, a smaller configuration can be achieved, and the reading positions of visible light and infrared light are closer, enabling highly accurate extraction and restoration of disappearing information. That is, there is no image shift due to multiple readings, and correction can be performed with high positional accuracy.

[0043] The image processing unit 43 executes various image processes according to the purpose of use of the image data. Note that the image processing unit 43 may be realized by a hardware circuit or may be realized by a CPU executing a program.

[0044] Here, FIG. 6 is a block diagram showing the functional configuration of the image processing unit 43. As shown in FIG. 6, the image processing unit 43 includes a feature amount detection unit 431 as a first width detection unit, a document size determination unit 432 as a width determination unit, and a document cutting unit 433.

[0045] The image processing unit 43 detects the feature amount of the subject or the background portion 26 by the feature amount detection unit 431 from at least one of the visible image and the invisible image obtained by the image reading device 101. Examples of the feature amount include, for example, an edge between the background portion 26 and the document 100. Although details will be described later, the image processing unit 43 uses the detected feature amount for the correction processing of the image itself.

[0046] The feature amount detection unit 431 functions as an edge detection unit that detects the edge of the subject in the main scanning direction. More specifically, the feature amount detection unit 431 detects an edge by a method such as detecting an edge from the density difference between the read document 100 and the background portion 26 or detecting a shadow between the document 100 and the background portion 26. The feature amount detection unit 431 regards a location where the amount of change in the image density exceeds a predetermined value as an edge of the document 100. Here, edge detection means detecting the edges of the left and right sides of the document 100 or detecting the edges of the detectable range of the main scanning area at the upper side of the document 100.

[0047] The document size determination unit 432 receives the edge detection result of the feature amount detection unit 431 or the detection result of the document width sensor 52 and determines the size of the document. More specifically, when the edges at both ends of the document 100 in the main scanning direction are detected by the feature amount detection unit 431 (not exceeding the detectable range), the document size determination unit 432 determines the main scanning width of the document 100.

[0048] The original document cutting section 433 cuts out the image of the original document 100 according to the size of the original document 100 determined by the original document size determination section 432, or the size of the original document 100 detected by the original document width sensor 52. In particular, when the original document size determination section 432 determines the size of the original document 100 using the edge detection result of the feature amount detection section 431, the original document cutting section 433 can cut out the original document 100 in just the right size.

[0049] Here, the difference in the spectral reflection characteristics due to the medium in the imaging unit 40 will be described.

[0050] FIG. 7 is a diagram showing the difference in spectral reflection characteristics due to the medium. FIG. 7 is a diagram showing the spectral reflection characteristics of two types of plain paper, paper type A and paper type B, which are generally used as the original document and are the objects to be read by the image reading apparatus 101, and the background portion 26. In FIG. 7, the graph of the dashed line is the graph of the spectral reflection characteristics of the plain paper (paper type A), the graph of the dotted line is the graph of the spectral reflection characteristics of the plain paper (paper type B), and the graph of the solid line is the graph of the spectral reflection characteristics of the background portion 26.

[0051] As shown in FIG. 7, in the visible wavelength range, the reflectance of the background portion 26, which is a white background, is higher than that of the plain paper (paper type A), but in the near-infrared (NIR) wavelength range, the reflectance of the background portion 26 is lower than that of the plain paper (paper type A).

[0052] Also, as shown in FIG. 7, it can be seen that the reflectance of the background portion 26 is higher than that of the plain paper (paper type B) in both the visible wavelength range and the near-infrared (NIR) wavelength range.

[0053] Here, FIG. 8 is a diagram exemplarily showing the difference between the visible image and the invisible image. As shown in FIG. 8, when the imaging unit 40 reads the reflected light, the spectral reflection characteristics are different between the background portion 26 and the original document, and images having different feature amounts are obtained for visible light and invisible light. Therefore, depending on the type of the subject and the type of the background portion 26, it is easier to obtain the target feature amount if the image to be detected is set in advance to be either a visible image or an invisible image.

[0054] For example, in the case of the example shown in FIG. 8, since the spectral reflectance characteristic difference between the invisible image and the background portion 26 is larger for paper type A than the visible image, the detection target of the feature amount can be set as the invisible image. Conversely, for paper type B, it can be set as the visible image.

[0055] Note that feature amounts may be extracted from both the visible image and the invisible image, and selection or integration may be performed from the results thereof.

[0056] Subsequently, the feature amount detection unit 431 will explain an example of edge detection of the document 100 which is the subject, and an example of correction of the inclination and position of the document.

[0057] FIG. 9 is a diagram showing an example of edge detection of the subject, FIG. 10 is a diagram showing an example of correction of the inclination and position of the document, and FIG. 11 is a diagram showing information obtained from the edge of the subject. For example, as shown in FIG. 9, when extracting the edge between the background portion 26 and the document 100 from the image, it is preferable to reduce the reflectance of the background portion 26 and use the invisible image. Also, as shown in FIG. 10, when performing correction of the inclination and position of the document and cropping of the document image, it is preferable to reduce the reflectance of the background portion 26 and use the invisible image. When reading with invisible light in this way, since the invisible light reflectance of the background portion 26 is low, a bright image of the document 100 and a dark image of the background portion 26 can be obtained. Since the difference between the document 100 and the background portion 26 can be clearly understood, edges can be easily detected. That is, the density difference between the document 100 and the background portion 26 can be widened, and edge detection can be performed with higher accuracy.

[0058] As shown in FIG. 11, an edge refers to the boundary between the document 100 which is the subject and the background portion 26. By detecting such an edge, as shown in FIG. 11, the position, inclination, size, etc. of the document 100 which is the subject can be recognized. And from the position, inclination, and size of the document 100 which is the subject, image correction corresponding to the position, inclination, and size of the document 100 which is the subject can also be performed in subsequent processing.

[0059] FIG. 12 is a diagram exemplarily showing an edge detection method. As an edge detection method, as shown in FIG. 12(a), for example, a method of applying a first derivative filter to the entire image and binarizing based on whether each pixel exceeds a predetermined threshold can be mentioned. At that time, depending on the threshold value, horizontal edges may appear continuously vertically by several pixels (the same is true vice versa). This is mainly because the edge is blurred due to the MTF characteristics of the optical system. Therefore, as shown in FIG. 12(b), in order to obtain representative edge pixels for calculating the regression line formula and size detection described later, for example, there is a method of selecting the center of continuous pixels (part a shown in FIG. 12(b)).

[0060] FIG. 13 is a diagram showing an example of feature amounts using edges. As the feature amounts, those using edges rather than the edges themselves extracted from the image may be used. Examples include, as shown in FIG. 13, a regression line formula calculated using the least squares method or the like from the extracted edge point group, and the area (set of positions) inside the edge. Regarding the regression line formula, there is a method of obtaining one linear formula from all edge information for each side, but there is also a method of calculating linear formulas by dividing into a plurality of regions and selecting or integrating representative ones. In that case, as methods for deriving the final linear formula, a straight line with the median as the slope and a method of obtaining the average value of each linear formula can be mentioned.

[0061] FIG. 14 is a diagram showing the selection of the linear formula in the regression line formula. By the process of calculating linear formulas by dividing into a plurality of regions and selecting or integrating representative ones, as shown in FIG. 14, even when there is damage such as the edge of the original document 100 as the subject being missing, the inclination of the original document 100 as the correct subject can be recognized.

[0062] As in the above processing, the feature amount detection unit 431 can detect the area of the original document 100 as the subject by extracting the edge of the original document 100 as the subject as the feature amount.

[0063] Incidentally, as described above, the image reading apparatus 101 of the present embodiment can detect the width of the original document 100 using the original document width sensor 52.

[0064] As shown in FIG. 3, for example, the original document width sensor 52 is composed of a plurality of light receiving elements (52a, 52b, 52c) arranged in the width direction of the original document 100. The light receiving elements (52a, 52b, 52c) of the original document width sensor 52 are placed at positions where it is possible to determine the size of the original document 100 of any standard size. Therefore, when the original document 100 of a standard size is passed through, the original document size of the original document 100 is determined from the position information of the light receiving elements of the original document width sensor 52 that have responded.

[0065] Next, the flow of the image cropping process in the image reading apparatus 101 will be described.

[0066] As described above, the image reading apparatus 101 of the present embodiment has two width detection units for different original documents 100. The first width detection unit extracts the edges of the original document from the image data by image processing and detects the original document size. The second width detection unit detects the original document size of the original document 100 from the original document detection result by the original document width sensor 52.

[0067] Here, FIG. 15 is a flowchart showing the flow of the image cropping process. As shown in FIG. 15, the image reading apparatus 101 controls the reading unit 30 to read the original document 100 (step S1).

[0068] Next, the feature amount detection unit 431 executes edge detection of the image of the read original document 100 (step S2). Subsequently, the original document size determination unit 432 detects the original document size from the edge detection result (step S3).

[0069] When the original document size determination unit 432 determines that the original document size of the original document 100 has been detected normally (Yes in step S4), the original document size determination unit 432 determines the original document size of the original document 100 from the edge detection result (step S5). Here, the case where the original document size determination unit 432 has detected the original document size of the original document 100 normally means that the original document size of the original document 100 has been detected within a predetermined size range (for example, when the original document size between the minimum paper size guaranteed by the product and the maximum paper size has been detected, etc.).

[0070] On the other hand, when the original size determination unit 432 determines that the original size of the original 100 cannot be detected normally (No in step S4), the original size determination unit 432 determines the original size of the original 100 from the detection result (sensor information) of the original width sensor 52 for the original 100 for which the image has been read (step S6). Here, the case where the original size determination unit 432 cannot detect the original size of the original 100 normally indicates the case where the detection of the original size of the original 100 is "abnormal". For example, the case where the detection of the original size of the original 100 is "abnormal" includes the case where the edge cannot be detected, or the case where the edge is detected but the image size is detected to be smaller than the predetermined size (for example, the case where it is detected to be less than the minimum paper size guaranteed by the product).

[0071] That is, in the present embodiment, when the original size determination unit 432 cannot detect the original size of the original 100 normally, the original size of the original 100 is determined using the detection result (sensor information) of the original width sensor 52.

[0072] When originals 100 of different sizes are mixed and bundled, the side guide plate 212 of the tray 21 must be adjusted according to the largest size among the original bundles. Therefore, if the position information detected by the original length detection sensors 213 and 214 of the side guide plate 212 is used as the original size, even if there are small-sized originals 100 in the original bundle, they have to be processed as large-sized originals 100, resulting in an increase in data size.

[0073] On the other hand, as in the present embodiment, by using the detection result of the original width sensor 52 installed in the conveyance path 23, it is possible to detect the size closest to the original size for each original 100. Therefore, even when originals 100 of different sizes are bundled, the size can be determined for each original 100.

[0074] Returning to FIG. 15, finally, the original cutting unit 433 cuts out the image according to the size detected by the original size determination unit 432 or the size detected by the original width sensor 52 (step S7).

[0075] Thus, according to this embodiment, even if for some reason the edge detection at both ends of the document 100 in the main scanning direction by the feature amount detection unit 431 is not completed normally, since the method for detecting the document size by the detection of the document width sensor 52 installed in the other conveyance path 23 is different, the possibility of failure due to the same factor is low, and it becomes possible to detect the document size.

[0076] In addition, the detection of the document size by the document width sensor 52 cannot detect the exact size of the document 100 such as the edge detection at both ends of the document 100 in the main scanning direction by the feature amount detection unit 431. However, since the detection of the document size does not fail except for physical failures of the document width sensor 52, the reliability is very high. In a conventional reading device, for example, when automatic size detection fails during mixed loading of different widths where regular-sized documents and irregular-sized documents are mixed, a size that is significantly different from the correct document size is detected by using the width of the side fence instead of the width of each subject. However, according to this embodiment, the document size (width of each subject) can be surely detected without failure.

[0077] In this embodiment, as shown in FIG. 3, the document width sensor 52 arranges a plurality of light receiving elements (52a, 52b, 52c) in the width direction of the document 100 in accordance with the size of the standard document of each document 100 from the side guide plate 212. However, the present invention is not limited to this.

[0078] For example, as shown in FIG. 16, the document width sensor 52 may arrange a plurality of light receiving elements (52a, 52b, 52c, 52d, 52e, 52f) separately on the left and right sides of the conveyance path 23.

[0079] Also, as shown in FIG. 17, the document width sensor 52 arranges a plurality of light receiving elements (52a, 52b, 52c) side by side in the conveyance path 23, and installs a guide plate sensor 61 having a plurality of light receiving elements (61a, 61b, 61c) on the side guide plate 212 side of the tray 21 to detect the position of the slid side guide plate 212.

[0080] In the present embodiment, the original document width sensor 52 of the ADF 102 is applied as the second width detection unit, and the original document size detected by the original document width sensor 52 is applied. However, the present invention is not limited to this. As long as the method is other than edge detection, the second width detection unit may detect the original document without using a sensor. For example, the presence or absence of the original document is determined at a plurality of predetermined positions in the image read by the reading unit 30, and the original document width is determined using the information on the original document presence or absence determination positions at the positions where the original document is determined to be present. With this method, since it is an image process different from edge detection, even if edge detection fails, the original document can be detected. Since the presence or absence of the original document at a predetermined position is determined, the exact size of the original document cannot be detected like edge detection. However, since the image data inside the original document is used instead of the unstable original document edge portion that is easily affected by the state of the original document, the original document size can be determined with high reliability, and the number of sensors can be reduced, so the cost can be reduced.

[0081] That is, for example, the image processing unit 43 may be applied as the second width detection unit, and the original document size detected based on the image data read by the reading unit 30 of the flatbed type may be applied. This will be described in detail below.

[0082] FIG. 18 is a view of the contact glass 11 seen from above, showing the relationship between the original document placement area on the contact glass 11 and the positions of the original document size detection spots SP1 to SP4. In FIG. 18, the sizes of standard original documents to be detected when the original document 100 is placed in accordance with the original document placement reference, which is the side guide plate 212, and a configuration example of the scanner light source block (unit of the light source 13 that can be individually controlled for ON / OFF) are shown. The image reading apparatus 101 detects the size of the original document 100 by the original document size determination unit 432 according to the combination of the reading results of the image data of each of the original document size detection spots SP1 to SP4.

[0083] FIG. 19 is a diagram showing an example of image data levels when the document size determination unit 432 determines the presence or absence of a document 100 in the main scanning direction by document size detection spots SP1 to SP3. When the image reading apparatus 101 detects the width of the document 100 in the main scanning direction, it acquires the image data in the main scanning direction at a position corresponding to the "main scanning width detection area", and detects the end of the document 100 using the average data of the three document size detection spots. When blank sheets of each size are placed on the contact glass 11, the combination of the main scanning position and the image data level (after shading correction) is as shown in FIG. 19. The image reading apparatus 101 determines the main scanning width by detecting the document end position from the image data in the document placement area. Note that for width detection, it is also possible to simplify the calculation by using the average data in the SP1 to SP3 areas.

[0084] Also, when the image reading apparatus 101 detects the width of the document 100 in the sub-scanning direction, it detects the presence or absence of the document 100 based on the image data level of the document size detection spot SP4. Then, the image reading apparatus 101 determines the size and orientation of the placed document 100 by combining the main scanning width detection result and the sub-scanning width detection result as shown in Table 1.

[0085]

Table 1

[0086] That is, as shown in FIG. 19, for example, if the image data level exceeds the document presence / absence determination threshold at any of the document size detection spots SP1 to SP3 in the main scanning direction, the document size determination unit 432 determines that the size of the document 100 is A4 (landscape) or A3. Whether the size of the document 100 is A4 (landscape) or A3 is determined by the image data level of the document size detection spot SP4.

[0087] In this way, by detecting the document by the second width detection unit using a method different from that of the first width detection unit and without using a sensor, it is possible to determine the image size inexpensively and without information loss from the document.

[0088] (Second Embodiment) Next, the second embodiment will be described.

[0089] In the second embodiment, the process for determining the document size using the document width sensor 52 is different from that in the first embodiment. Hereinafter, in the description of the second embodiment, the description of the same parts as in the first embodiment will be omitted, and the parts different from the first embodiment will be described.

[0090] Here, FIG. 20 is a diagram showing the process for determining the document size using the document width sensor 52 according to the second embodiment.

[0091] According to the first embodiment, when there is a possibility that the irregular-sized document 100 is mixed, it is not known where the document edge is between the light-receiving element of the document width sensor 52 that has reacted with the actual document 100 and the light-receiving element of the document width sensor 52 one outside thereof. Therefore, if the document size is determined at the position of the light-receiving element of the document width sensor 52 that has reacted in the same manner as the regular-sized document 100, the document edge may be cut off and the image may be missing.

[0092] Therefore, in this embodiment, as shown in FIG. 20, the document size determination unit 432 determines the document size of the document 100 using the position of the light-receiving element of the document width sensor 52 that is one or more outside the position of the light-receiving element of the document width sensor 52 that has detected the document 100. By doing so, the edge of the document 100 is prevented from being cut off, and the width of the margin is minimized, so that the problem of an increase in the data amount can be avoided.

[0093] As described above, according to this embodiment, it is possible to determine the image size such that no information is missing from the document by determining the size that is closest to the actual document size and larger than the actual document size.

[0094] Incidentally, as shown in FIG. 21, even when the document width sensor 52 arranges a plurality of light receiving elements (52a, 52b, 52c, 52d, 52e, 52f) separately on the left and right sides of the conveyance path 23 (see FIG. 16), similarly, by determining the document width outside one of the reacted light receiving elements, the document 100 can be set to an optimal width without edge breakage.

[0095] Also, as shown in FIG. 22, when the document width sensor 52 arranges a plurality of light receiving elements (52a, 52b, 52c) side by side in the conveyance path 23 and installs a guide plate sensor 61 having a plurality of light receiving elements (61a, 61b, 61c) on the side guide plate 212 side of the tray 21 to detect the position of the side guide plate 212 (see FIG. 17), similarly, by determining the document width outside one of the reacted light receiving elements, the document 100 can be set to an optimal width without edge breakage.

[0096] (Third Embodiment) Next, the third embodiment will be described.

[0097] The third embodiment is different from the first embodiment or the second embodiment in that it provides a user interface capable of arbitrarily adjusting the image size of the detection result of the document width of the document 100. Hereinafter, in the description of the third embodiment, the description of the same parts as those in the first embodiment and the second embodiment will be omitted, and the parts different from the first embodiment and the second embodiment will be described.

[0098] Here, FIG. 23 is a block diagram showing the electrical connection of each part constituting the image reading apparatus 101 according to the third embodiment, and FIG. 24 is a block diagram showing the functional configuration of the image processing unit 43.

[0099] As shown in FIGS. 23 and 24, the image reading apparatus 101 of the present embodiment includes an operation unit 44. The operation unit 44 is, for example, a display with a touch panel.

[0100] FIG. 25 is a diagram showing a display example in the operation unit 44 in the case of ADF reading. As shown in FIG. 25, the operation unit 44 realizes a user interface UI-1 that can arbitrarily adjust the image size of the image of the detection result of the document width of the document 100 by the document size determination unit 432.

[0101] For example, the detection of the document width of the document 100 by the document width sensor 52 may vary depending on the assembly accuracy. Therefore, in the present embodiment, the user interface UI-1 can be used to individually adjust the detection result of the document width of the document 100 by the document width sensor 52. Specifically, as shown in FIG. 25, the document size determination unit 432 can adjust the detected document width of the document 100 according to at least one of the inputs in the four directions of X1, X2, Y1, and Y2 from the user interface UI-1.

[0102] Accordingly, according to the present embodiment, it is possible to correct the deviation of the document detection result due to variations caused by assembly accuracy or to adjust the size according to the user's preference.

[0103] In the case of flatbed reading as well, the operation unit 44 realizes a user interface UI-2 that can arbitrarily adjust the image size of the image of the detection result of the document width of the document 100 by the document size determination unit 432. FIG. 26 is a diagram showing a display example in the operation unit 44 in the case of flatbed reading.

[0104] As shown in FIG. 26, the document size determination unit 432 can adjust the detected document width of the document 100 according to at least one of the inputs in the four directions of X1, X2, Y1, and Y2 from the user interface UI-2.

[0105] Thus, according to the present embodiment, the detected document size can be finely adjusted.

[0106] The program executed by the image forming apparatus 1 of each of the above embodiments is provided by being recorded on a computer-readable recording medium such as a CD-ROM, a flexible disk (FD), a CD-R, a DVD (Digital Versatile Disc) in a file in an installable format or an executable format.

[0107] Further, the program executed by the image forming apparatus 1 of each of the above embodiments may be configured to be stored on a computer connected to a network such as the Internet and downloaded via the network. Further, the program executed by the image forming apparatus 1 of each of the above embodiments may be configured to be provided or distributed via a network such as the Internet. Further, the program executed by the image forming apparatus 1 of each of the above embodiments may be configured to be provided by being pre-installed in a ROM or the like.

[0108] The program executed by the image forming apparatus 1 of each of the above embodiments has a module configuration including the above-described respective parts (feature amount detection unit 431, original document size determination unit 432). As actual hardware, the CPU (processor) reads the program from the above storage medium and executes it, whereby the above respective parts are loaded onto the main storage device, and the feature amount detection unit 431 and the original document size determination unit 432 are generated on the main storage device.

[0109] In each of the above embodiments, an example in which the reading apparatus of the present invention is applied to a multifunction machine having at least two functions among a copying function, a printer function, a scanner function, and a facsimile function is described. However, the present invention can be applied to any image forming apparatus such as a copying machine, a printer, a scanner device, and a facsimile device.

[0110] In each of the above-described embodiments, the image reading device 101 of the image forming apparatus 1 is applied as the reading device, but the present invention is not limited thereto. As the definition of the reading device, any device capable of obtaining a reading level may be used, such as a line sensor of an equal magnification optical system (contact optical system: CIS method) shown in FIG. 27(a), even if it does not read as an image. The device shown in FIG. 27(a) moves a line sensor or an original to read information of a plurality of lines.

[0111] Furthermore, the reading device can also be applied to a banknote conveying device shown in FIG. 27(b), a white line detection device of an automated guided vehicle (AGV) shown in FIG. 27(c), and the like.

[0112] The subject of the banknote conveying device shown in FIG. 27(b) is a banknote. The feature amount detected by the banknote conveying device is used for correction processing of the image itself and the like. That is, the banknote conveying device shown in FIG. 27(b) recognizes the inclination of the banknote by edge detection and performs skew correction using the recognized inclination.

[0113] The subject of the white line detection device of the automated guided vehicle shown in FIG. 27(c) is a white line. The feature amount output by the white line detection device of the automated guided vehicle can be used for determining the moving direction of the automated guided vehicle and the like. That is, the white line detection device of the automated guided vehicle recognizes the inclination of the white line area by edge detection and determines the moving direction of the automated guided vehicle using the recognized inclination. Further, in the white line detection device of the automated guided vehicle, moving direction correction according to the position and orientation of the automated guided vehicle can also be performed in subsequent processing. For example, in the case of an automated guided vehicle, processing such as stopping driving when a thickness different from the known thickness of the white line is detected can also be executed.

[0114] Here, FIG. 28 is a diagram showing another modification example of the reading device, and FIG. 29 is a diagram showing an arrangement example of the original width sensor. The example shown in FIG. 28 shows an application example to an image reading device 200 used at the time of packaging of a load such as a production site as the reading device.

[0115] The subjects of the image reading device 200 shown in FIG. 28 are packages A, B, and C of different sizes that are goods in transit. As shown in FIG. 28, when packages A, B, and C of different sizes are conveyed by the belt conveyor 201, the feature amounts (edges) of packages A, B, and C are detected by the image reading device 200 of the present invention, so that the widths of the packages can be detected. When detecting the feature amounts of packages A, B, and C, visible light is effective for black packages, and invisible light is effective for white packages.

[0116] Note that in this case, the background portion 26 may be the surface of the belt conveyor 201, or a dedicated background portion 26 may be arranged with the reading position of the image reading device 200 being the gap of the belt conveyor 201.

[0117] The image reading device 200 detects the feature amounts (edges) of the conveyed packages A, B, C, etc., and detects the widths of the packages based on the detection results of the feature amounts of packages A, B, C. By selecting the size of the container for packaging, it is possible to reduce waste such as using an overly large container.

[0118] Also, when the width detection by image processing on the image of the packages A, B, C, etc. being conveyed read by the image reading device 200 fails, the width of the packages is determined from a sensor 202 installed in the conveyance path including the belt conveyor 201 and detecting the width sizes of the conveyed packages A, B, C, etc. Thereby, by selecting the size of the container or packaging material for packaging based on the detection result, it is possible to reduce waste such as using an overly large container or packaging material.

[0119] Aspects of the present invention are as follows, for example. <1> An illumination unit that irradiates light onto a subject; An imaging unit that receives the light reflected by the subject and generates an image; A first width detection unit that detects the width of the subject; A second width detection unit that detects the width of the subject by a method different from that of the first width detection unit; A width determination unit that determines the size of the subject; comprising, the width determination unit when the detection by the first width detection unit is normal, determines the width of the subject based on the detection result of the first width detection unit, when the detection by the first width detection unit is abnormal, determines the width of the subject based on the detection result of the second width detection unit, characterized by a reading device. <2> The first width detection unit detects the edges at both ends in the main scanning direction of the imaging unit for the subject to detect the width of the subject. The reading device according to <1>, characterized by this. <3> Further includes a transport unit that transports the subject, The second width detection unit determines the width of the subject using a sensor that detects the passing position of the subject during transport. The reading device according to <1> or <2>, characterized by this. <4> The sensor is a plurality of light receiving elements, The width determination unit determines the width of the subject using the position information of one or more outer light receiving elements among the light receiving elements that have reacted to the subject during transport. The reading device according to <3>, characterized by this. <5> The second width detection unit discriminates the presence or absence of the subject at a plurality of predetermined positions in the image generated by the imaging unit, and determines the width of the subject using the information on the presence or absence discrimination positions of the subject at one or more outer sides of the positions where the subject is discriminated as present. The reading device according to any one of <1> to <4>, characterized by this. <6> The illumination unit irradiates the subject with visible light and invisible light, The imaging unit receives the visible light and invisible light reflected by the subject, and captures a visible image and an invisible image. The first width detection unit detects the edge of the subject from at least one of the visible image and the invisible image. The reading device according to <2>, characterized by this. <7> The width determination unit adjusts the width of the subject according to an input from the user interface. The reading device according to any one of <1> to <6>. <8> The subject is a transported object. The reading device according to <1>. <9> The reading device according to any one of <1> to <8>, and an image forming unit, An image processing apparatus characterized by comprising. <10> An illumination unit that irradiates light onto a subject, an imaging unit that receives the light reflected by the subject and generates an image, a first width detection unit that detects the width of the subject, a second width detection unit that detects the width of the subject by a method different from that of the first width detection unit, and a width determination unit that determines the size of the subject. A reading method in a reading device comprising: The width determination unit, When the detection by the first width detection unit is normal, a step of determining the width of the subject based on the detection result of the first width detection unit; When the detection by the first width detection unit is abnormal, a step of determining the width of the subject based on the detection result of the second width detection unit; A reading method characterized by including. <11> A computer that controls a reading device including an illumination unit that irradiates light onto a subject, an imaging unit that receives the light reflected by the subject and generates an image, a first width detection unit that detects the width of the subject, and a second width detection unit that detects the width of the subject by a method different from that of the first width detection unit, A program that functions as a width determination unit for determining the size of the subject, The width determination unit, When the detection by the first width detection unit is normal, determine the width of the subject based on the detection result of the first width detection unit, When the detection by the first width detection unit is abnormal, determine the width of the subject based on the detection result of the second width detection unit, A program characterized by the above.

Explanation of Signs

[0120] 1 Image processing apparatus 13 Illumination unit 40 Imaging unit 43 Image processing unit, second width detection unit 52, 61, 202 Sensors, second width detection unit 101 Reading device 102 Conveying unit 103 Image forming unit 431 Feature amount detection unit, first width detection unit 432 Document size determination unit, width determination unit

Prior art documents

Patent documents

[0121]

Patent Document 1

Claims

1. An illumination unit that irradiates an object with light, An imaging unit that receives the light reflected by the object and generates an image, A first width detection unit that detects the width of the object, A second width detection unit that detects the width of the object by a method different from that of the first width detection unit, A width determination unit that determines the size of the object, Comprising, The width determination unit, When the detection by the first width detection unit is normal, determines the width of the object based on the detection result of the first width detection unit, When the detection by the first width detection unit is abnormal, determines the width of the object based on the detection result of the second width detection unit, A reading device characterized by the above.

2. The first width detection unit detects the edges at both ends in the main scanning direction of the imaging unit with respect to the object to detect the width of the object, The reading device according to claim 1, characterized by the above.

3. Further comprising a conveyance unit that conveys the object, The second width detection unit determines the width of the object using a sensor that detects the passing position of the object during conveyance, The reading device according to claim 1, characterized by the above.

4. The sensor is a plurality of light receiving elements, The width determination unit determines the width of the object using the position information of one or more outer light receiving elements among the light receiving elements that have reacted to the object during conveyance, The reading device according to claim 3, characterized by the above.

5. The second width detection unit discriminates the presence or absence of the object at a plurality of predetermined positions in the image generated by the imaging unit, and determines the width of the object using the information on the presence or absence discrimination positions of the object at one or more outer sides of the positions where the object is discriminated as present, The reading device according to claim 1, characterized by the above.

6. The illumination unit irradiates the object with visible light and invisible light, The imaging unit receives the visible light and invisible light reflected by the object and captures a visible image and an invisible image, The first width detection unit detects the edge of the object from at least one of the visible image and the invisible image, The reading device according to claim 2, characterized by the above.

7. The width determination unit adjusts the width of the object according to an input from a user interface, The reading device according to claim 1, characterized by the above.

8. The object is a transported object, The reading device according to claim 1, characterized by the above.

9. A reading device according to any one of claims 1 to 8, An image forming unit, An image processing device characterized by comprising the above.

10. An imaging method for an imaging apparatus, comprising: an illumination unit that irradiates an object with light; an imaging unit that receives the light reflected by the object and generates an image; a first width detection unit that detects the width of the object; a second width detection unit that detects the width of the object by a method different from that of the first width detection unit; and a width determination unit that determines the size of the object. The width determination unit when the detection by the first width detection unit is normal, determines the width of the object based on the detection result of the first width detection unit; when the detection by the first width detection unit is abnormal, determines the width of the object based on the detection result of the second width detection unit. The imaging method is characterized by including the above. **Claim 11** A program for causing a computer that controls an imaging apparatus, the imaging apparatus including: an illumination unit that irradiates an object with light; an imaging unit that receives the light reflected by the object and generates an image; a first width detection unit that detects the width of the object; and a second width detection unit that detects the width of the object by a method different from that of the first width detection unit, to function as a width determination unit that determines the size of the object, wherein the width determination unit when the detection by the first width detection unit is normal, determines the width of the object based on the detection result of the first width detection unit, and when the detection by the first width detection unit is abnormal, determines the width of the object based on the detection result of the second width detection unit. The program is characterized by the above.

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